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herpes, STDs

IgM blood test for herpes. Just say no.

herpes-virus-armed-and-dangerous_2Routine screening blood tests for herpes are not recommended by the Centers for Disease Control. When I say routine screening I mean a scenario such as, “I want to get checked for everything, ok?”

Blood tests for herpes do have a place in specific clinical situations, but that’s for another post.

But say you did get a herpes blood test (even though it’s not recommended many people seem to get it done) and it’s positive for something called IgM antibodies. Armed with these results your doctor proceeds to tell you that these results mean you caught herpes recently, so you start to freak out….

Stop right there.

A positive herpes IgM test means nothing. I’ve posted about this before but enough people continue to leave comments on my herpes posts asking about their positive IgM test that it bears repeating…

A herpes IgM test is never, ever, ever indicated. Not ever, because it doesn’t mean much of anything. 

“Impossible,” you say. “My doctor ordered it, so it must be a valid test.”

Well, no.

Let’s review antibodies. When we are exposed to infections we make antibodies. Antibodies are proteins produced by the immune system that fight bacteria and viruses, hopefully containing these infections. IgM antibodies are made first, within weeks, but they don’t hang around. Think of them as first responders. IgG antibodies take longer to produce, but once present you typically have them for life.

However, with herpes this response system is a little different. The herpes virus is never cleared by the immune system. Once you stop shedding the virus it takes up shop in the nerves (the dorsal root ganglia to be specific). From time to time the virus is reactivated, either producing ulcers or just asymptomatic shedding of the virus. How often the virus is reactivated and how much virus is shed depends on many factors (a topic for another post).

It is this ability to stay dormant and then reactivate that is a defining characteristic of herpes viruses, but this also affects IgM production. When herpes is reactivated, even though it is not a brand new infection, the body often produces IgM. So, the presence of IgM antibodies against herpes don’t tell you if this is a recent infection or a reactivation and so is of no use clinically. In addition, the IgM tests offered by commercial labs have not been well vetted as type specific, meaning they may not reliably distinguish between IgM for herpes type 1 and type 2 (and remember, by the age of 30 almost everyone is positive for heroes type 1).

Just because a lab offers a test doesn’t mean that the test is A) useful for your medical care and B) reliable.

Despite this, many people get tested for herpes IgM.

If you are getting a blood test for herpes, ask your doctor specifically what test that means. If your doctor is ordering an IgM test then go somewhere else, because it means they don’t know enough about herpes to be testing you in the first place.

Remember, this post is not direct medical advice.

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Discussion

23 thoughts on “IgM blood test for herpes. Just say no.

  1. I work in a setting where I see A LOT of young adults who want the blood testing done for HSV without any symptoms, as if it’s part of a physical exam. It takes me FOREVER to counsel them about why they want it, what causes them to think it’d be helpful, or what they think it means. THANK YOU for this.

    Posted by illbeyournursetoday | June 17, 2013, 7:18 am
  2. As the medical director at SexualHealth.com, we get many inquiries about herpes IgM testing. I couldn’t agree with your post more Dr. Jen. I don’t fault primary care providers for not knowing that herpes IgM testing is worthless because its the exception to the rule when it comes to early infections and IgM. In addition to teaching people not to get IgM testing, I also like to remind people that they can have type 2 herpes for years, even decades, without knowing it and without having a visible outbreak. Don’t break up with your partner over a new herpes diagnosis, because you assume that partner is cheating on you. Your current partner may not be the person who exposed you to herpes. Lastly, keep it in perspective. Its a drag to find out you have herpes, but it is a bother more than a medical concern and you shouldn’t allow it to ruin your life. Herpes does not define who you are. Nice, clean, smart and monogamous people can have herpes. It doesn’t mean you’re a bad person. There is a wonderful book written by a nurse out in Seattle, Terri Warren. Its called The Good News About The Bad News. I recommend it to all of my patients with herpes.

    Posted by DrLisaOldson | June 17, 2013, 11:53 am
  3. But the presence of IgM antibodies does mean the person ‘has’ HSV1 and/or HSV2 correct? This means something. This person can now pass it to another person via viral shedding. They might not even know if they have it orally or in their genitals, but why would it be better not to know? A positive IgM test means you have Herpes Simplex in some form either recently acquired or in the past, correct or incorrect? Oral and Genital Herpes both have their unique challenges in terms of living though genital does have the bigger stigma. One part of lowering the stigma associated with genital herpes is to make more people aware of the great prevelance of HSV in our population.

    Posted by Juliet | June 17, 2013, 12:42 pm
    • No, IgM does not mean that you have herpes in some form. A positive test could be herpes 1 (which everyone has), herpes 2, or it could be cross reaction with another herpes virus, such as CMV (which a lot of people have) or varicella zoster (which almost everyone has).

      Doing a test that can’t possible give you an accurate answer does not help raise awareness, it causes fear and confusion and should not be ordered.

      Posted by Dr. Jen Gunter | June 18, 2013, 6:41 am
      • I understand, Thanks Dr. Gunter. That is a clearly different story. There are accurate blood tests that can identify HSV1 / HSV2 status like igG, I see no reason why this should not be offered instead of IgM, it is more important I would think to know your status that when you acquired the infection. I believe *sometimes* there are other ways to suspect if it is a new infection, such as high fever along with lesions and new sexual partner, but in the end if you have it you can spread it whether you are asymptomatic or not. Most people think that when they are tested ‘clean’ for ‘everything’ that includes HSV which unfortunately contributes to the anti-HSV stigma.

        Posted by Juliet | June 18, 2013, 9:06 am
      • I really appreciate your post clarifying the Igm test.

        Each year (for the past 5 years) I am tested for STD’s as part of my physical. My doctor always orders a panel from the hospital that include an igg and igm test.

        On 3 occasions, the igm test came back positive with 1.6, 1.3 and 1.2 values. Over 5 years the igg test for type 1 & 2 always came back negative with a value of <0.91.

        So I have always been skeptical of why this igm test is ordered. If I initially tested igm positive 5 years ago (and 2 subsequent times), but never seroconverted to igg antibodies then something must be cross reacting on the test.

        Would you agree?

        Posted by UMfan80 | September 27, 2013, 7:47 am
      • Thank you so much for the informative article. A lot of confusing information out there regarding testing.

        Question: Given the issues with blood testing, what is one’s course of action if they have been exposed to HSV-2 and are symptomatic with no external sores, lesions or blisters for swabbing? What testing should be performed?

        Posted by Jon Hauger | March 5, 2014, 4:00 pm
  4. Reblogged this on EVERYONE HAS HERPES! and commented:
    Just in time for me to start blogging here, one of my favorite doctor-bloggers posts about herpes! It’s a brief but informative discussion of why the herpes IgM test is a meaningless test, and you shouldn’t get it. She also links to previous herpes posts, which you should check out if you still have herpes questions or if you want to hear the info from an actual doctor.

    Posted by keelyellenmarie | June 18, 2013, 7:56 pm
  5. A question if one has Hsv 2 and the other partner that don’t have it, and do oral sex to the one that has the Hsv 2 can the partner that don’t have herpes get it?

    Posted by Confused | June 20, 2013, 5:05 pm
  6. So far as I know, I do not have Herpes 1 or 2. When I get into a new a relationship, is there a test that I can use to definitively tell my new partner I don’t have the virus? This is the main reason I’ve heard of people getting the IgM test – to prove you are negative. Am I correct in taking away from this that there is never a way to be sure until you actually see lesions?

    Posted by Renee | June 21, 2013, 11:43 am
  7. Hi Doc! So its funny I just came across this article, but I just spoke with my doctor about my blood results I recently got back. I found out three years ago that apparently I have herpes, not sure which kind though. My girlfriend at the time both woke up with outbreaks, in complete shock after being intimate the night before. Neither of us has ever had a positive test for HSV at that point, but she did get waxed on her bikini line a couple days before. Could this have been the cause??

    Since then we have only had that initial outbreak, never a single one in 3 1/2 years now. I have now been tested at my internist for HSV and first one 3 years ago was negative, not just yesterday he said it was negative as well. How is this possible that I could have two negative HSV tests but still had that initial outbreak, that was tested by a dermatologist and deemed positive from a culture. Who is correct here? I would think the blood test would be the most accurate no? Appreciate your guidance.

    Posted by Mark | June 26, 2013, 5:09 pm
  8. Hi Jen, thanks for your informative post!

    Out of interest, can a viral culture (swab) test detect a subclinical or asymptomatic infection? I recently had a swab test done as a matter of routine at a clinic because I got a scab down there (actually from a sport injury). Here in NZ they seem to test for the sake of testing haha.

    If, for example, I were to have an asymptomatic infection would a culture test detect this?

    S)

    Posted by sj | July 30, 2013, 3:15 pm
  9. Hi Dr.Jen, I’ve got chicken pox when I was kid. 10 months ago I made hsv 1&2 test and I remember that it IgM, anyhow the result was 1.10 which is borderline. I have no symptoms. could that called false positive or as you said it mentioned to antibodies of varicella zoster. all the best

    Posted by Jon | August 12, 2013, 6:22 pm
  10. I recently went to the emergency room because my anus had a burning ripping just a very excruciating uncomfortable pain it looked like a rash of some sort I would’ve never guessed the doctor was going to tell me it looks like herpes so he took a blood test and I got the results back the igg test says negative for both types while the igm test say abnormal for both hsv1 and 2 in the same sentence what does that mean. I don’t have a primary doctor nor do I have an appointment to see a doctor for another week I’m so confused and don’t know what to think help me please?

    Posted by Bianca bland | September 16, 2013, 5:02 pm
  11. I have a question i need help?i went to my doctor back in march and i was tested negative to blood work and swab test i went again last week 6months later my doctor said im tested for negative for everything again but she said im exposed to herpes..iam so confused does that mean i have it?she said no you dont have the virus but you was exposed to it.someone please help :(

    Posted by Merra | October 4, 2013, 1:24 am
  12. Can you tell me, what does Herpes II IGG : >200 mean???? plz thanks

    Posted by Kimberly Lalla | November 13, 2013, 4:39 pm
  13. I prefer to learn what herpes is and what are herpes symptoms, than doing a blood test.

    Posted by chondry | January 24, 2014, 1:12 am
  14. Herpes is one of the most popular disease, for some people (including me) trying to talks about herpes requires a lot of things and to be honest, this is my first time reading an article about the IgM blood test. Thanks

    Posted by Anna | February 6, 2014, 6:21 pm
  15. I was recently tested for IgG 1 and 2 it came back negative about three days later I got one sore on my private area..I went to my ob dr and he said it was herpes for sure…then he cultured it and sent it to the lab it came back negative then he had me redo the IgG and also the IgM the IgG 1 and 2 came back negative but the IgM came back postive..he said I for sure have herpes 2 I don’t know what to believe…could you please help.Thank. For your time

    Posted by Elizabeth | February 13, 2014, 7:20 pm
  16. I given my blood to test for HIV. And second time i given same like that due to fear that time result human immune deficency syndrome 1&2 negative. And i had again doubt also i given third time in that time screening test for 1&2 is negative. Now ibm getting fully itch. now till also iam getting fobia. What i have to do sir. . . . .

    Posted by Prakash | June 30, 2014, 7:01 am
  17. So, where should I go to get a blood test for herpes?

    Posted by amanda pepper | July 1, 2014, 1:36 am
    • You can get a serum IgG test for herpes from any lab and any doctor can order it. It must be a type specific test (I believe there is a link n the article to the specific brands of tests). When getting tested for herpes it is important to ask yourself how those results will change how you live your life if they are positive and if they are negative.

      Posted by Dr. Jen Gunter | July 1, 2014, 7:16 am

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